Simulation of the interaction between an edge dislocation and a '100' interstitial dislocation loop in α-iron

Atomic-level simulations are used to investigate the interaction of an edge dislocation with '100' interstitial dislocation loops in alpha-iron at 300 K. Dislocation reactions are studied systematically for different loop positions and Burgers vector orientations, and results are compared for two different interatomic potentials. Reactions are wide-ranging and complex, but can be described in terms of conventional dislocation reactions in which Burgers vector is conserved. The fraction of interstitials left behind after dislocation breakaway varies from 25 to 100%. The nature of the reactions requiring high applied stress for breakaway is identified. The obstacle strengths of '100' loops, 1/2'111' loops and voids containing the same number (169) of point defects are compared. (10 0) loops with Burgers vector parallel to the dislocation glide plane are slightly stronger than '100' and 1/2'111' loops with inclined Burgers vector: voids are about 30% weaker than the stronger loops. However, small voids are stronger than small 1/2'111' loops. The complexity of some reactions and the variety of obstacle strengths poses a challenge for the development of continuum models of dislocation behaviour in irradiated iron. (C) 2008 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.